Revert the non-cleanup part of r230769 because it introduced a non-determinism found only in the names of symbols.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231058 91177308-0d34-0410-b5e6-96231b3b80d8

utils/TableGen/CodeGenRegisters.cpp

@@ -258,8 +258,6 @@ CodeGenRegister::computeSubRegs(CodeGenRegBank &RegBank) {
 
     // Look at the possible compositions of Idx.
     // They may not all be supported by SR.
-    // NOTE: Iteration order does not matter here because the EnumValue's
-    // of subreg indices are unique.
     for (CodeGenSubRegIndex::CompMap::const_iterator I = Comps.begin(),
            E = Comps.end(); I != E; ++I) {
       SubRegMap::const_iterator SRI = Map.find(I->first);

utils/TableGen/CodeGenRegisters.h

@@ -75,7 +75,8 @@ namespace llvm {
     std::string getQualifiedName() const;
 
     // Map of composite subreg indices.
-    typedef DenseMap<CodeGenSubRegIndex *, CodeGenSubRegIndex *> CompMap;
+    typedef std::map<CodeGenSubRegIndex *, CodeGenSubRegIndex *,
+                     deref<llvm::less>> CompMap;
 
     // Returns the subreg index that results from composing this with Idx.
     // Returns NULL if this and Idx don't compose.